40X Microscope objective

ABSTRACT

A three member microscope objective having a numerical aperture of substantially 0.66 and a magnification of substantially 40X provides a substantially flat image field of about 24mm.

Unlted St Shoemaker 40X MICROSCOPE OBJECTIVE [75] Inventor: Arthur H. Shoemaker, East Aurora,

[73] Assignee: American Optical Corporation,

Southbridge, Mass.

[22] Filed: Apr. 26, 1974 [21] Appl. No.: 464,383

[52] US. Cl. 350/229; 350/175 ML; 350/176 [51] Int. Cl. G02B 9/12; G02B 21/02 [58] Field of Search 350/225, 229, 175 ML, 176

[56] References Cited UNITED STATES PATENTS 3,552,830 1/1971 Shoemaker 350/225 X July 8, 1975 3,552,831 1/1971 Shoemaker 350/225 x Primary Examiner.lohn K. Corbin Attorney, Agent, or FirmAlan H. Spencer; William C. Nealon; H. R. Berkenstock, Jr.

[5 7 ABSTRACT A three member microscope objective having a numerical aperture of substantially 0.66 and a magnification of substantially 40X provides a substantially flat image field of about 24mm.

2 Claims, 1 Drawing Figure 1 40 X MICROSCOPE OBJECTIVE BACKGROUND OF THE INVENTION The values of the objective as stated herein are independent of normal manufacturing tolerances.

What is claimed is:

l. A microscope objective which is well corrected for chromatic image aberrations. spherical aberration coma and astigmatism and has three elements aligned along an optical axis, which comprises a concavoproviding a substantially flat image field of about it) com'ex P i i single I first e|emem- 11 double 24mm when used with a telescope Objective as convex positive doublet II as a second element and a scribed in U S p NO. 3355234 double convex positive doublet III as a third element. said elements having the following optical parameters: DRAWING AND INVENTION The drawing is an optical diagram of the microscope l5 objective X having lens elements, I. II and III in optical alignment along an optical axis extending from object plane 0. The first element I is a concavo-convex posi- Thick 5% who tive singlet; the second element II is a double convex Radiu t-S SPIICC Index Number positive doublet and the third element III is a double S: convex positive doublet. The parameters of objective X M are set forth in Table I wherein the axial thicknesses of i=- T ND( 1 successive lens elements are designated TI to T5, and I 5 h M 1 PM the successive axial spaces from the object plane (des- Rg= 0.7315F S ignated O) are $1 to S3. The successive lens radii are 6x designated R1 to R8 where the minus sign applies 13:41:84]: ND 1 to surfaces whose center of curvature lies on the object 0 5 852,? 3:354: side of their vertices. The refractive indices and Abbe ll R,= 1.2737F numbers of the glasses in the successive lenses are ab- T1: ND( solute fixed values designated ND(l) to ND(S) and uieSoSF 1119669 v(3)=56.l3 I/( l to 11(5) respectively and F is the focal length of the HIMF S: objective in millimeters. liOXfiSF TABLE I Refractive Abbe Lens Radius Thickness Space Index Number s,=0.i59iF R, 0.572OF I T =0.7659F ND( I )=l .78833 v( I )=50.47

R ==-0.73l5F s,=0.o46si= R3= 4.l284F T=O.3282F ND(2)=I.8049I v(2)=25.42 II R, 1.2737F T3=O.6565F ND(3)=I.69669 v(3)=56.13 R,=- 1.6057F Sf-LO865F RF 11.4873F T4==0.3282F ND(4)=I.80784 v(4)=40.74 III R1= 1.3057F T,=0.6565F ND(5)=I.5224I 11(5)=59.5O R 3.2142F A specific embodiment of the present invention is an R.,= 11.4873F I ND(4)= ob ective with a focal length of 4.570mm and the opti 0 5282: LX078 M2404 cal values set forth in Table II. in R,= 1.3057F T,-,= ND(5)= TABLE II 0.6565F 1.52241 v(5)=59.50 R, 3.2143F. Lens Radius Thickness Space R 2.6l4 wherein axial thicknesses of successive lens element I T,=3.50O

3343 are Tl to TS, successive axial spaces are Sl to S3, suc- -F cessive lens radii are Rl to R8 where applies to sur- R; 18.867

T2=L50Q faces whose center of curvature lies on the ob ect side ll F 2 T 000 of the vertices refractive indices and Abbe numbers of R3} 7338 the successive lenses are ND( l to ND(S), 1 (1) to 11(5) 7 S=i=4965 5 respectively, and F is the focal length of the objective RF TFLSOO in millimeters. III R; 5.967 2. The microscope objective of claim I wherein F is T -,=3.0UO 4 R,-i4.es9 

1. A microscope objective which is well corrected for chromatic image aberrations, spherical aberration, coma and astigmatism and has three elements aligned along an optical axis, which comprises a concavo-convex positive singlet I as a first element, a double convex positive doublet II as a second element and a double convex positive doublet III as a third element, said elements having the following optical parameters:
 2. The microscope objective of claim 1 wherein F is 4.570. F 